This invention relates to a safety device for revolving doors and, in particular, for the doors revolving about a vertical axis placed in the center of the opening.
A revolving door has as its main feature the controlling and the limiting of the flow of persons coming through it in both directions until stopping it completely when the rotation of the door about its vertical axis is prevented.
There are known numerous application forms of revolving doors which are provided with hydraulical, pneumatical or electrical apparatus to produce, on command, a rotation and/or a locking of the revolving doors.
Similar applications are frequently employed for compulsory entrances and exits on the premises open to the public such as banks, offices and the like, where for safety reasons, it is desirable that the traffic of persons in the entrance and in the exit be sufficiently orderly and controllable.
Therefore it is particularly important, in such applications, that the revolving doors be provided with safety devices being able to face suitably emergency situations when there arises a need to make possible, even in the case when the revolving doors remain for any reason, locked, the normal flow of persons and/or even any increase thereof.
Similar emergency situations can be determined by a simple blocking up of the revolving door in a fixed position, caused by a breakdown or by an interruption of the correct operation of its drive means, or by external causes such as, for example, situations that put in danger the physical safety of persons, that are present on the premises accessible via the doors, and require fast evacuation of the above-mentioned premises.
For the time being there are not known any efficacious devices that are likely to assure and to allow an increase, in case of necessity, in revolving doors, the flow of persons which come through them.